In general, use a supported version of Postgres, MariaDB, or MySQL.
CakePHP 4 requires Postgres 9.4+, MariaDB 5.6+, or MySQL 5.6+.
DBAL 4 will require Postgres 10+, MariaDB 10.2.7+, or MySQL 5.7+. Registry uses DBAL for schema management, so installing or updating the database schema will require these versions when Registry updates to DBAL 4.